Cassette for accommodating electrically conductive film

ABSTRACT

A cassette for recording an image on a film which has an electrically conductive layer which is wound on a reel rotatably supported within a cassette casing includes a contact piece for grounding which is mounted on a reel body. A clamp is engaged with the reel body so as to press the film against the contact piece. The contact piece slide-contacts a reel retainer secured to the cassette casing, thereby allowing the film to be electrically connected to the reel retainer through the contact piece. The reel container is connected to a contact member which projects to the outside of the cassette casing, and this contact member is connected to a contact provided on an apparatus into which the cassette is loaded, thereby effecting grounding.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a cassette for accommodating a materialin the form of a tape wound on a reel, such as an electrophotographicfilm, which needs to be grounded. More particularly, the presentinvention pertains to a cassette for accommodating an electricallyconductive film or other similar materials which includes a reelprovided with a contact piece for grounding.

2. Description of the Related Art

Electrophotographic film, when applied to, for example, a documentstorage and retrieval system, provides various advantages which cannotpractically be obtained from conventional films made of a silver halidephotosensitive material, as is described in the specification ofJapanese Patent Laid-Open No. 79234/1984. Electrophotographic film isexpected to become more practically utilizable by accommodating it in acassette which will facilitate its management, storage and handling.

This electrophotographic film is formed from a transparent base in theform of a tape which includes, for example, polyester as its principalcomponent, together with a transparent electrically conductive layer anda transparent photoconductive insulating layer which are, in that order,coated on the base, the electrically conductive layer needing to begrounded when, for example, it is electrically charged.

It may be considered reasonable to assume that electrophotographic filmaccommodated in a cassette is grounded through the reel on which thefilm is wound.

In general, it is advantageous to employ a reel molded from a syntheticresin from the viewpoint of attaining reduction in costs and weight.However, it is not possible to obtain any electrical connection betweenthe electrophotographic film and the synthetic resin reel solely bywinding the film on the reel.

SUMMARY OF THE INVENTION

In view of the above circumstances, it is a primary object of thepresent invention to provide a cassette for accommodating a film whichhas an electrically conductive layer which incudes a reel provided witha contact piece for grounding so that the film can be grounded throughthe reel.

To this end, the present invention provides a cassette for accommodatingan electrically conductive film, which comprises: a reel body having arecess formed in the outer peripheral portion of its hub; a contactpiece for grounding disposed on the reel body such that a portion of thecontact piece is positioned in the recess; and a clamp fitted into therecess such as to define a part of the outer peripheral portion of thehub of the reel body, whereby one end of the film which needs to begrounded is clamped between the contact piece and the clamp when fittedinto the recess.

By virtue of the above arrangement, one end of the electricallyconductive film is clamped between a portion of the contact piece forgrounding and the clamp and therefore electrically connected to thecontact piece. Thus, it is possible to ground the film through anotherportion of the contact piece by an appropriate means.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinvention will become more apparent from the following description ofthe preferred embodiments thereof, taken in conjunction with theaccompanying drawings, in which like reference numerals denote likeelements, and in which:

FIGS. 1 to 15 show in combination a first embodiment of the cassette foraccommodating an electrically conductive film according to the presentinvention, of which:

FIG. 1 is an exploded perspective view of the whole of the firstembodiment;

FIG. 2 shows the interior of the lower cassette casing;

FIG. 3 shows the interior of the upper cassette casing;

FIG. 4(A) is an exploded perspective view of one of the reels;

FIG. 4(B) is a perspective view of the reel shown in

FIG. 4(A), as viewed from the underside thereof;

FIG. 4(C) is an enlarged perspective view of the clamp shown in FIG.4(A);

FIG. 5 is an enlarged plan view of an essential portion of the reel;

FIG. 6 is a sectional view taken along the line VI--VI of FIG. 5;

FIG. 7 is a plan view of the lower cassette casing with various partsassembled therein;

FIG. 8 is a sectional view taken along the line VIII--VIII of FIG. 7;

FIG. 9(A) is an exploded perspective view of one of the guide rollers;

FIG. 9(B) is a plan view of the hub member of the guide roller shown inFIG. 9(A);

FIG. 9(C) is a sectional view taken along the line IXC--IXC of FIG.9(B);

FIG. 10 is a perspective view of one of the brake levers;

FIG. 11(A) is a partially-cutaway perspective view of the release piece;

FIG. 11(B) is a sectional view of the release piece;

FIG. 11(C) is a perspective view of another example of the releasepiece;

FIG. 12 is a side view of the lock plate;

FIG. 13(A) is a perspective view of the cassette casing body and theguard panel before they are assembled together;

FIG. 13(B) shows a portion of the cassette casing body as viewed fromthe direction indicated by the arrow XIIIB in FIG. 13(A);

FIG. 14 is a perspective view of the guard panel as viewed from theunderside thereof; and

FIG. 15 is a perspective view of the cassette casing body and the guardpanel in their assembled state.

FIG. 16(A) is a perspective view which schematically shows the cassetteholder section of an apparatus into which the cassette according to thepresent invention is loaded;

FIG. 16(B) is a sectional view of the cassette holder section shown inFIG. 16(A);

FIGS. 17(A) and 17(B) are perspective views of reel retainers inaccordance with second and third embodiments of the present invention,respectively;

FIG. 17(C) is a sectional view taken along the line XVIIC--XVIIC of FIG.17(B);

FIG. 18 is a perspective view of a fourth embodiment of the presentinvention;

FIG. 19 is a plan view of the fourth embodiment shown in FIG. 18;

FIG. 20 is a sectional view taken along the line XX--XX of FIG. 19;

FIG. 21 is an enlarged view of a portion of the fourth embodimentindicated by the arrow XXI in FIG. 20; and

FIGS. 22 and 23 are fragmentary sectional views, corresponding to FIG.21, which respectively show fifth and sixth embodiments of the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1 to 15 show in combination a first embodiment of the cassette foraccommodating an electrically conductive film according to the presentinvention. The embodiment will be described below in detail for each ofthe constituent elements thereof.

Lower Cassette Casing

As shown in FIGS. 1 and 2, a lower cassette casing 10 includes asubstantially U-shaped bottom panel 12 having its right and left frontend portions projecting forwardly. The bottom panel 12 has peripheralwalls projecting upwardly from the periphery and the inner surfacethereof. The peripheral walls consist of a rear wall 14 standing fromthe rear edge of the bottom panel 12, left and right side walls 16, 18respectively standing from the left and right side edges of the panel12, and a front wall 20 which extends over from the front edge portionof the panel 12 toward the left and right side edges. The rear wall 14and the side walls 16, 18 are integrated together to provide a U-shapedperipheral wall portion extending along the outermost periphery of thebottom panel 12.

The front wall 20 is disposed such that a portion thereof which isprovided at the front edge of the bottom panel 12 is positioned at theoutermost periphery of the panel 12, while portions of the front wall 20which are provided at the left and right end portions of the bottompanel 12 are positioned on the inner sides of the walls 16, 18,respectively. The portion of the front wall 20 positioned on the innerside of the left side wall 16 extends rearwardly in parallel with thewall 16 and then curves inwardly so as to be contiguous with the rearwall 14. The portion of the front wall 20 positioned on the inner sideof the right side wall 18 extends rearwardly in parallel with the wall18 with a slight spacing therebetween and then curves outwardly so as tobe contiguous with the wall 18.

A portion of that part of the front wall 20 which extends parallel tothe left side wall 16 projects upwardly beyond the other portion of saidpart so as to provide a projecting wall 22. A recess 24 having asemicircular cross-section is formed in the upper end surface of theprojecting wall 22. A portion of the front wall 20 which extends overfrom the portion parallel to the right side wall 18 to the frontedge-side portion of the wall 20 projects upwardly beyond the otherportion of the front wall 20 in this section, thus providing aprojecting wall 26. A recess 28 having a semicircular cross-section isformed in the upper end surface of the portion of the projecting wall 26which extends parallel to the right side wall 18.

In the lower cassette casing 10, partition walls, columnar andcylindrical projections, recesses and protuberances are formed on theinner surface of the bottom panel 10 and on the inner side of the aboveperipheral walls, as described later. All of these portions are formedon the lower cassette casing 10 by integral molding from a syntheticresin.

The inside of the lower cassette casing 10 is partitioned by partitionwalls so as to define various chambers, that is, left and right reelchambers 30, 32 for accommodating a pair of reels, left and right guideroller chambers 34, 36 for accommodating a pair of guide rollers, abrake mechanism chamber 38 for accommodating a brake mechanism for thereels, a lock plate chamber 40 for accommodating a lock plate whichlocks a guard panel, and an independent chamber 42 in which a tab isdisposed.

The left and right reel chambers 30 and 32 are respectively positionedon the left and right sides of a central partition wall 44 which isprovided such as to project upwardly from the bottom panel 12 and at aposition which is slightly closer to the right end of the lower cassettecasing 10 than the lateral center thereof. Circular through-holes 46 areprovided in the bottom panel 12 and at the respective centers of theleft and right reel chambers 30 and 32. An annular protuberance 48having a rectangular cross-section is formed on the inner surface of thebottom panel 12 and along the peripheral edge of each of thethrough-holes 46. An annular protuberance 50 having a rectangularcross-section is concentrically formed around each annular protuberance48. The portion of the bottom panel 12 between each pair of annularprotuberances 48 and 50 is slightly recessed from the surface of thepanel 12, thus providing an annular recess 51. The edge of eachthrough-hole 46 on the outer surface of the bottom panel 12 is chamferedto a substantial extent (see FIG. 8).

The left and right guide roller chambers 34 and 36 are respectivelypositioned in the left and right projecting portions at the front end ofthe lower cassette casing 10 so that the chambers 34 and 36 arerespectively adjacent to the left and right reel chambers 30 and 32. Acylindrical projection 52 is formed on the bottom panel 12 such as toproject from the center of each of the left and right guide rollerchambers 34 and 36 as far as the upper ends of the peripheral walls. Aflange 52A is formed at the root portion of each of the projections 52.A recess 52B (see FIG. 13(B)) which has an inside diameter larger thanthe inside diameter of the hollow portion of the cylindrical projection52 is formed in the outer surface of the bottom panel 12 at the portionthereof which is formed with the flange 52A. The hollow portion of theprojection 52 opens into the recess 52B so as to communicate with theoutside.

The left and right guide roller chambers 34, 36 and the left and rightreel chambers 30, 32 are respectively partitioned by partition walls 54and 54. The distal end portion of each wall 54 is bent so as to providean opening and define a partition wall 56 which extends into the guideroller chamber 34 (or 36). Further, notches 58 are formed in twoportions of the front wall 20 which respectively face the left and rightguide roller chambers 34 and 36, thereby allowing the chambers 34 and 36to communicate with the outside.

The brake mechanism chamber 38 is positioned in the center of the rearend portion of the lower cassette casing 10 adjacent to the left andright reel chambers 30 and 32. The chamber 38 is further partitionedinto three chambers by the central partition wall 44 and two partitionwalls 60 which extend parallel to the prolongation of the wall 44, thecentral chamber serving as a release piece chamber 62, and the left andright chambers serving as brake lever chambers 64, respectively.

The release piece chamber 62 has a circular through-hole 66 provided inthe bottom panel 12 and at the center of the chamber 62. The peripheraledge of the through-hole 66 on the outer surface of the bottom panel 12is chamfered. Two columnar projections 68 and 70 are provided in each ofthe brake lever chambers 64 so as to project from the bottom panel 12beyond the upper ends of the peripheral walls, the projections 68 and 70being disposed adjacent to each other laterally of the lower cassettecasing 10. Flanges 68A are respectively formed at the root portions ofthe inner columnar projections 68.

Notches 72 are partially formed in the partition walls 60, respectively,which partition the brake mechanism chamber 38 into the release piecechamber 62 and the left and right brake lever chambers 64, therebyallowing the chambers to communicate with each other. The left and rightbrake lever chambers 64 and the left and right reel chambers 30, 32 arerespectively partitioned by partition walls 74 which are partiallyopened so that each pair of adjacent chambers communicate with eachother. Recesses 76 are formed in the bottom panel 12 near the openedportions of the walls 74 such as to extend over the chambers 64 and thechambers 30, 32, respectively.

The lock plate chamber 40 is positioned in the left-hand side portion atthe front end of the lower cassette casing 10. The chamber 40 has a rearchamber portion 82 which is laterally defined by the left side wall 16and that portion of the front wall 20 which is positioned on the innerside of the wall 16, the rear end of the portion 82 being defined by apartition wall 80 both ends of which are contiguous with the walls 16and 20. A columnar projection 83 is provided in the rear chamber portion82 so as to project from the bottom panel 12 beyond the upper ends ofthe peripheral walls.

The lock plate chamber 40 further has a front chamber portion 88 whichis laterally defined by a lock plate retaining wall 84 contiguouslyextending from the inwardly bent front end 16A of the left side wall 16and that portion of the front wall 20 positioned on the inner side ofthe wall 16, the front end of the portion 88 being defined by a frontwall portion 86 extending leftwardly from said portion of the front wall20. The lock plate retaining wall 84 is not contiguous with the frontwall portion 86, and an opening 90 is provided between the wall 84 andthe wall portion 86. Further, a notch 92 is formed in the lock plateretaining wall 84.

The independent chamber 42 is positioned adjacent to the rear end of thelock plate chamber 40. The independent chamber 42 is laterally definedby the left side wall 16 and that portion of the front wall 20positioned on the inner side of the wall 16, and the front end of thechamber 42 is defined by the partition wall 80, while the rear endthereof is defined by a partition wall 94. The portion of the bottompanel 12 which constitutes the bottom of the independent chamber 42 ispartially cut off from the body of the panel 12 so that it is contiguouswith the body at a few (two) portions thereof, the partially cut portionof the panel 12 serving a tab 96. When the tab 96 is pressed by a fingeror the like, the tab 96 can readily be broken at its joint with the bodyof the bottom panel 12 and separated from the lower cassette casing 10.

Three cylindrical projections 98 are respectively provided in the leftand right corners at the rear end of the lower cassette casing 10 and atthe center of the front end thereof so that they project from the innersurface of the bottom panel 12 as far as the upper ends of theperipheral walls. The hollow portion of each of the projections 98 alsoopens to the outer surface of the bottom panel 12. A partition wall 100is formed in the hollow portion of each projection 98 and at a positionslightly lower than the distal or upper end thereof so that the hollowportion is divided into upper and lower portions. A circularthrough-hole 102 is provided in the center of the partition wall 100,whereby the upper and lower hollow portions are communicated with eachother through the through-hole 102. The head of a tapping screw 318(described later) abuts against the partition wall 100 so as to beretained thereby.

The greater part of the peripheral walls of the lower cassette casing10, the partition walls 54 between the left and right reel chambers 30,32 and the left and right guide roller chambers 34, 36, and thepartition walls 56 and 94 which are contiguous with the walls 54 are soshaped that substantially a half of the upper end surface of each ofthese walls slightly projects from the other surface portion in the formof a step for the purpose of connecting the lower cassette casing 10 andan upper cassette casing 104 (described later) by means of spigot joint.

Upper Cassette Casing

As shown in FIGS. 1 and 3, the upper cassette casing 104 includes a toppanel 106 which is constituted by a rectangular body portion 106A,together with left and right end portions 106B and 106C which projectfrom the body portion 106A slightly forwardly (these portions 106B and106C are located on the upper side of the body portion 106A in FIG. 3,since the upper cassette casing 104 is drawn upside down in FIG. 3).Peripheral walls project downwardly from the periphery and the innersurface of the top panel 106. The left and right end portions 106B and106C of the top panel 106 are disposed such as to be different in levelfrom the body portion 106A, that is, they are positioned lower than thebody portion 106A as viewed in FIG. 1. The peripheral walls consist of arear wall 108, left and right side walls 110, 112 and a front wall 114,which are so shaped that they respectively correspond to and abutagainst the rear wall 14, the left and right side walls 16, 18 and thefront wall 20 provided on the lower cassette casing 10.

A portion of that part of the front wall 114 which extends parallel tothe left side wall 110 is recessed so as to provide a recessed wall 116.A recess 118 having a semicircular cross-section is formed in the lowerend surface (the upper end surface, in the case where the upper cassettecasing 104 is placed upside down, as shown in FIG. 3) of the wall 116.The recessed wall 116 is so shaped that it receives the projecting wall22 formed on the front wall 20 of the lower cassette casing 10, and whenthe projecting wall 22 is fitted into the recessed wall 116, a shaftsupporting bore 120 having a circular cross-section is defined by therecess 118 and the recess 24 which is formed in the projecting wall 22,the recesses 118 and 24 facing each other (see FIG. 13(B)).

A portion of the front wall 114 which extends over from the portionparallel to the right side wall 112 to the front edge-side portion ofthe wall 114 is recessed so as to provide a recessed wall 122. A recess124 having a semicircular cross-section is formed in the lower endsurface of the recessed wall 122. The wall 122 is so shaped that itreceives the projecting wall 26 formed on the front wall 20 of the lowercassette casing 10, and when the projecting wall 26 is fitted into therecessed wall 122, a shaft supporting bore 126 having a circularcross-section is defined between the recess 124 and the recess 28 whichis formed in the projecting wall 26, the recesses 124 and 28 facing eachother (see FIG. 13(A)).

The inside of the upper cassette casing 104 is partitioned by partitionwalls such as to define upper chambers which respectively correspond tothose formed in the lower cassette casing 10, that is, left and rightreel chambers 128, 130, left and right guide roller chambers 132, 134, abrake mechanism chamber 136, a lock plate chamber 138, and anindependent chamber 140.

Unlike the left and right reel chambers 30 and 32 formed in the lowercassette casing 10, the left and right reel chambers 128 and 130 have nopartition wall therebetween and therefore are communicated with eachother. Circular ribs 142 and radially extending linear ribs 144 areformed within each of the chambers 128 and 130 such as to project fromthe top panel 106 for the purpose of reinforcing the panel 106.

Three columnar relatively short projections 146 are formed within eachof the reel chambers 128 and 130 such as to project from the top panel106, the projections 146 within the chamber 128 being located on theside thereof which is closer to the left end of the casing 104, and theprojections 146 within the chamber 130 being located on the side thereofwhich is closer to the right end of the casing 104 asymmetrically withthe former projections 146 with respect to the longitudinal axis of thecasing 104. Further, only the right reel chamber 130 has twothrough-holes 148 with a circular cross-section formed in serieslongitudinally of the casing 104 in the right end portion of the chamber130.

A cylindrical projection 150 is formed at the center of each of the leftand right guide roller chambers 132 and 134 so as to project from thetop panel 106 as far as the vicinity of the distal ends of theperipheral walls. A flange 150A is formed at the root portion of each ofthe projections 150. When the upper cassette casing 104 is connected tothe lower cassette casing 10, these cylindrical projections 150 arepositioned directly above the cylindrical projections 52 respectivelyformed within the left and right guide roller chambers 34 and 36 of thelower cassette casing 10. In this case, the respective ends of each pairof corresponding projections 150 and 52 abut against each other. It isto be noted that the hollow portion of each projection 150 has aslightly smaller inside diameter than that of the hollow portion of eachprojection 52, and the proximal end of each projection 150 is closed andtherefore not communicated with the outside.

The left and right guide roller chambers 132, 134 and the left and rightreel chambers 128, 130 are respectively partitioned by partition walls152. The distal end portion of each wall 152 is bent so as to provide anopening and define a partition wall 154 which extends into the guideroller chamber 132 (or 134) in a manner similar to that in the case ofthe lower cassette casing 10. Further, notches 156 are similarly formedin two portions of the front wall 114 which respectively face the leftand right guide roller chambers 132 and 134, thereby allowing thechambers 132 and 134 to communicated with the outside. When the uppercassette casing 104 is connected to the lower cassette casing 10, thenotches 156 respectively face the notches 58 formed in the front wall 20of the casing 10, thereby defining tape inlet/outlet ports 158 having arectangular cross section (see FIG. 13(A)).

Unlike the brake mechanism chamber 38 of the lower cassette casing 10,the inside of the brake mechanism chamber 136 is not partitioned intothree chambers. Further, no opening is formed in partition walls 160which partition the chamber 136 from the left and right reel chambers128 and 130. Two parallel guide walls 162 having a relatively low heightare provided in the center of the brake mechanism chamber 136 so as toextend longitudinally of the upper cassette casing 104. Two guide walls164 slightl project from the outer surface of each of the guide walls162 laterally of the casing 104, the guide walls 164 having the sameheight as that of the guide walls 162. A step-like projecting portion166 is formed at the distal end of each of the guide walls 164.

Two cylindrical projections 168 are respectively formed at left andright positions in the rear portion of the brake mechanism chamber 136such as to project from the top panel 106 as far as the vicinity of thedistal ends of the peripheral walls. When the upper cassette casing 104is connected to the lower cassette casing 10, the projections 68 formedin the brake mechanism chamber 38 of the casing 10 are respectivelyfitted into the inner hollow portions of the projections 168.

The lock plate chamber 138 has a cylindrical projection 170 projectingfrom the top panel 106 as far as the vinicity of the distal ends of theperipheral walls. When the upper cassette casing 104 is connected to thelower cassette casing 10, the columnar projection 83 formed in the lockplate chamber 40 of the casing 10 is fitted into the inner hollowportion of the cylindrical projection 170. Unlike the independentchamber 42 of the lower cassette casing 10, the independent chamber 140has no tab formed on a portion of the panel 106 which constitutes thebottom of the chamber 140. The chamber 140 is formed in the form of aparallelepiped only one side of which is open.

A projection 171 projects from the left corner at the front end of thetop panel 106 of the upper cassette casing 104. A recess 173 is definedbetween the projection 171 and that portion of the front wall 114 whichextends parallel to the left side wall 110 (see FIG. 13(B) incombination with FIG. 3).

Three cylindrical projections 172 are respectively formed at the leftand right corners at the rear end portion and at the center of the frontend portion of the upper cassette casing 104 such as to project from theinner surface of the top panel 106 beyond the distal ends of theperipheral walls. It is to be noted that the hollow portion of each ofthe cylindrical projections 172 is closed at the proximal end thereofand therefore not communicated with the outside.

The greater part of the peripheral walls of the upper cassette casing104, the partition walls 152 between the left and right reel chambers128, 130 and the left and right guide roller chambers 132, 134, and thepartition walls 154 which are contiguous with the walls 152 are soshaped that substantially a half of the distal end surface of each ofthese walls slightly projects from the other surface portion in the formof a step for the purpose of connecting the upper cassette casing 104and the lower cassette casing 10 by means of spigot joint. A partitionwall which defines the rear end of the independent chamber 140 is madeflush with the above-described surface portion, which projects in theform of a step, whereby the wall 174 and the partition wall 94 of theindependent chamber 42 of the lower cassette casing 10 are connectedtogether by means of spigot joint.

A group of ridges are formed on the outer surface of the top panel 106of the upper cassette casing 104 so that they define guide rails 176arranged in a substantially U-shaped configuration such as to surroundthe through-holes 148 formed in the right reel chamber 130, as shown inFIG. 1. The degree by which the ridges (rails) 176 project from theouter surface of the top panel 106 is very small. Four recesses 178 arerespectively defined between pairs of adjacent ridges 176. Two of thefour recesses 178 which are positioned on one side of the substantiallyU-shaped guide rail, constituted by the ridges 176, are respectivelyoffset from the other two recesses 178 which are positioned on the otherside of the rail as viewed in the longitudinal direction of the uppercassette casing 104 so that each of the through-holes 148 is positionedbetween the two sides of the rail and on the imaginary diagonal lineconnecting the diagonally facing recesses 178 as viewed in the lateraldirection of the casing 104.

All the portions of the upper cassette casing 104 are integrally moldedfrom a synthetic resin in a manner similar to that in the case of thelower cassette casing 10.

Reel

Referring to FIGS. 1 and 4, each of the reels 180 consists of a flange182 and a hub 184 which are integrally molded from a synthetic resin. Amultiplicity of rectangular teeth 186 are formed along the outerperipheral surface of the flange 182 at equal spacings. The hub 184 isconstituted by a cylindrical inner tube 188 and a cylindrical outer tube190 which are connected by eight ribs 192 radially extending from theinner tube 188. The lower side of the inner tube 188 is open, while theupper side of the outer tube 190 is open, and the other sides of thetubes 188 and 190 are closed.

An annular protuberance 194 having a rectangular cross-section is formedon the lower side of the flange 182 such as to be concentrical with theflange 182. The outside diameter of the annular protuberance 194 is soset that the protuberance 194 is movably fitted into the correspondingthrough-hole 46 formed in the lower cassette casing 10. Another annularprotuberance 196 having a rectangular cross-section is concentricallyformed around the annular protuberance 194.

About an eigth part of the outer tube 190 of the hub 184 is cut off toprovide a recess. Two of the ribs 192 which extend radially from theinner tube 188 are respectively contiguous with the two end faces ofthis recess. These two ribs are denoted by a reference numeral 192A inorder to distinguish them from the other ribs. Each of the ribs 192Aextends upwardly so that the upper end thereof is higher than the upperends of the other ribs 192 and is flush with the upper end surface ofthe outer tube 190. Further, step portions 192B are formed on respectiveportions of the ribs 192A which are contiguous with the outer tube 190,the portions 192B projecting toward each other.

A portion of the outer peripheral surface of the inner tube 188 whichfaces the recess of the outer tube 190 is flattened so as to provide aflat-wall surface 193 (see FIG. 5 in combination with FIG. 4). A groove195 is formed in the circumferential center of the flat-wall surface193, the groove 195 extending vertically.

Two columnar relatively short projections 198 are formed on the uppersurface of the inner tube 188 so that the projections 198 are positionedon the same imaginary diametrical line of the inner tube 188 whichpasses through the groove 195 formed in the flat-wall surface 193. Nineprojections 200 are formed in the hollow portion of the inner tube 188at equal spacings such as to project from the inner surface toward thecenter thereof. These projections 200 have a trapezoidal cross-sectionand extend in the heightwise direction of the inner tube 188.

As shown in FIG. 6, the lower end 188A of the inner tube 188 projectsbeyond the undersurface of the flange 182. Ribs 202 are formed such asto connect the projecting end portion of the inner tube 188 and theannular protuberance 194 formed on the flange 182.

A clamp 204 is disposed in the recess formed in the outer tube 190 ofthe hub 184, whereby one end portion of a tape 222 is retained on thereel 180.

Clamp

As shown in FIGS. 1 and 4(C), the clamp 204 comprises: a base portion206 the outer periphery of which has a curvature substantially equal tothat of the outer periphery of the outer tube 190 of the hub 184; legplate portions 208 respectively extending from both ends of the baseportion 206 toward the center of the curvature of the outer periphery ofthe base portion 206; and a bent plate portion 210 having both endsthereof respectively connected to the leg plate portions 208 the portion210 having a V-shaped cross-section. A step portion 208B projects fromthe outer surface of the distal end portion of each of the leg plateportions 208. The above portions of the clamp 204 are integrally moldedfrom a synthetic resin.

The clamp 204 is disposed in the recess formed in the hub outer tube 190of each of the reels 180 as described above. At that time, a contactpiece 212 is simultaneously disposed in the recess.

Contact Piece

Referring to FIGS. 1 and 4, the contact piece 212 for grounding isconstituted by a single flat metal sheet formed by bending, embossingand shearing. The contact piece 212 is bent at right angles at itsapproximately central portion. The approximately central portion of oneside portion 212A of the bent contact piece 212 is subjected to bendingso as to provide a protuberant surface 214 having a semicircularcross-section, the surface 214 projecting outwardly. The center of thetop of the protuberant surface 214 is embossed so as to provide ahemispheric convex portion 216 projecting outwardly. Bores 218 areformed in the contact piece 212 by shearing, the bores 218 beingrespectively located on both sides of the protuberant surface 214 in thelongitudinal direction of the contact piece 212.

A rectangular notch 220 is formed in the other side portion 212B of thebent contact piece 212 by shearing. The notch 220 communicates with theoutside at one end thereof in the longitudinal direction of the contactpiece 212. The side portion 212B is slightly bent outwardly at aposition near the approximately central portion of the contact piece 212at which it is bent at right angles. The side portion 212B is furtherslightly bent inwardly at its approximately central portion.

Tape

As shown in FIG. 1, the tape 222 which is to be accommodated in thecassette casing body consists of a photosensitive tape 224, a magnetictape 226 which serves as a memory tape, and a leader tape 228, which arespliced together by pieces of splicing tape 230. An electricallyconductive adhesive tape 232 is bonded to the end of the photosensitivetape 224 opposite to the end thereof which is spliced to the magnetictape 226 by the splicing tape 230.

The photosensitive tape 224 is an electrophotographic film in the formof a tape which is formed from a transparent insulating base of, e.g.,polyester, together with an electrically conductive layer of,e.g.,Al,Au,ln₂ 0₃ ZnO, or CuI and a photoconductive insulating layer of,e.g., polyvinyl carbazole, which is an organic semiconductor, theselayers being, in that order, coated on the base.

It is to be noted that the electrically conductive -ayer can be formedby evaporating the above metal material on the base or by applying abinder containing the particles or power of the above metal material tothe base. Also, electrophotographic film which can be applied to thepresent invention is not limited to the example of the above embodiment,but well-known electrophotographic films can be applied to the presentinvention. The electrically conductive adhesive tape 232 is constitutedby a thin metallic tape provided thereon with an adhesive layer havingelectrically conductive particles, such as, carbon dispersed andcompounded therein.

When the electrically conductive adhesive tape 232 is bonded to thephotosensitive tape 224, the photoconductive insulating layer of thephotosensitive tape 224 is partially peeled, and the adhesive tape 232is bonded to the exposed electrically conductive layer.

Retaining of Tape on Reel

The tape 222 is retained on the reel 18 in the manner described below.

The contact piece 212 is first disposed on the hub 184 of the reel 180.The contact piece 212 is engaged with the hub 184 in such a manner thatthe projections 198 formed on the upper surface of the inner tube 188 ofthe hub 184 are respectively fitted into the bores 218 formed on oneside portion 212A of the contact piece 212. Since the diameter of thebores 218 and that of the projections 198 are so set that they aretight-fitted to each other, it suffices to employ tight-fitting alone.However, it is possible to reliably prevent the contact piece 212 fromcoming out of the hub 184 by thermally caulking the respective distalend portions of the projections 198 after they have been fitted into thebores 218.

Since one side portion 212A of the contact piece 212 is positioned inthe manner described above, the other side portion 212B is positionedsuch as to extend along the flat-wall surface 193 formed on the outerperipheral surface of the inner tube 188. In consequence, the upper endportion of the side portion 212B comes in plane contact with theflat-wall surface 193, while the lower end of the side portions 212Bcomes in point contact with the flat-wall surface 193.

Then, as shown in FIG. 5, the clamp 204 having one end portion of thetape 222 wound thereon is press-fitted into the recess formed in theouter tube 190 of the hub 184. The distal end portion of thephotosensitive tape 224 is retained on the reel 180 which isaccommodated in the right reel chamber, and the distal end portion ofthe leader tape 228 is retained on the reel 180 which is accommodated inthe left reel chamber. It is to be noted that the photosensitive tape224 is wound around the clamp 204 in such a manner that the electricallyconductive adhesive tape 232 is outward.

The step portions 208B of the clamp 204 are respectively retained by thestep portions 192B formed on the ribs 192A, whereby the clamp 204 isprevented from coming out of the recess in the radial direction of thereel 180. Further, as shown in FIG. 6, the central bent portion of thebent plate portion 210 enters the notch 220 formed in the contact piece212 and projects from the rear side of the contact piece 212 so that theupward movement of the bent plate portion 210 is limited by the upperend face of the notch 220, thus preventing the clamp 204 from coming outof the recess in the upward direction. It is to be noted that the distalend of the central bent portion of the bent plate portion 210 ispositioned within the groove 195 formed in the flat-wall surface 193.The clamp 204 is further press-fitted into the recess, so that the legplate portions 208 are deflected inwardly about their joints with thebase portion 206 and, at the same time, the bent plate portion 210 isalso deflected. Therefore, the leg plate portions 208 are respectivelypressed against the step portions 192B by means of the shape restoringforce. Accordingly, the clamp 204 is disposed on the hub 184 without anybacklash or play.

The tape 222 is pressed and clamped between the leg plate portion 208 ofthe clamp 204 and the ribs 192A and is further bent by a multiplicity ofangular portions as well as being supported in such a manner that thetape 222 is forced into the notch 220 of the contact piece 212 by thecentral bent portion of the bent plate portion 210. Thus, the tape 222is reliably retained on the reel 180.

Since the tape 22 is forced into the notch 220, the electricallyconductive adhesive tape 232 is reliably pressed against the contactpiece 212, whereby a reliable electrical connection is obtained betweenthem.

Thus, the reels 180 having the tape 222 retained thereon arerespectively accommodated in the left and right reel chambers 30 and 32of the lower cassette casing 10.

Disposition of Reel in Lower Cassette Casing

As shown in FIGS. 7 and 8, the reels 180 are respectively disposed inthe left and right reel chambers 30 and 32 of the lower cassette casing10 in such a manner that the annular protuberance 194 formed on theundersurface of the flange 182 of each reel 180 is fitted into thethrough-hole 46 formed in each of the chambers 30 and 32. Prior to thisfitting, a slide sheet 234 (see FIG. 1) made of a material having arelatively small surface friction coefficient, such as Teflon, is laidwithin each of the annular recesses 51, the slide sheet 234 having anoutside diameter smaller than the inside diameter of the annularprotuberance 50. Thus, the reels 180 are respectively accommodated inthe reel chambers 30 and 32, and the annular protuberance 196 formed onthe undersurface of the flange 182 of each reel 180 is positioned suchas to abut against the slide sheet 234 laid on the annular recess 51, asshown in FIG. 8.

In this state, the depth of each annular recess 51 is reduced by anamount corresponding to the thickness of the slide sheet 234.Consequently, the annular protuberances 48 and 50 formed in each of thereel chambers 30 and 32 are not in contact with the undersurface of theflange 182.

The intermediate portion of the tape 222 having both its endsrespectively retained on the reels 180 is passed over left and rightguide rollers 236.

Guide Roller

Referring to FIGS. 1 and 9, each of the guide rollers 236 is constitutedby a hub member 238 and two flange members 240, which are assembledtogether in one unit. Each of the members 238 and 240 is integrallymolded from a synthetic resin. The hub member 238 is composed of anouter tube 242 and an inner tube 244 which are connected together byribs 246 in one unit. The inner tube 244 is made longer than the outertube 242 so that both end portions of the inner tube 244 slightlyproject from the corresponding ends of the outer tube 242. Alarger-diameter portion 248 is formed around the outer periphery of thecentral portion of the inner tube 244. The larger-diameter portion 248projects in the form of a step beyond the outer peripheral surfaces ofthe other portions. The inside diameter of one end portion of the hollowportion of the inner tube 244 is made slightly larger than that of theintermediate portion, thereby providing larger-diameter portion 250A,while the inside diameter of the other end portion is made slightlysmaller than that of the intermediate portion so as to provide asmaller-diameter portion 250B.

The inner tube 244 and the outer tube 242 are connected by a total ofeight ribs 246 which are disposed radially at equal spacings. On oneside of the larger-diameter portion 248 of the inner tube 244, four ribs246 are disposed at equal spacings of 90°; on the other side, four ribs246 are disposed at equal spacing of 90° and 45° out of phase withrespect to the former ribs 246.

Each of the flange members 240 is constituted by an integral structurewhich is composed of a disk-shaped flange portion 252 having an openingin its center, and four leg portions 254 projecting from the flangeportion 252 at equal spacings. An annular protuberance 256 is formedalong the periphery of the opening of the flange portion 252 so as toproject therefrom in the form of a step. The leg portions 254 projectfrom the protuberance 256, and the inner side surface of each legportion 254 is contiguous with the end face of the opening of the flangeportion 252. The distal end portion of each leg portion 254 is bentinwardly so as to provide a hook-shaped retaining portion 258. Theundersurface of each retaining portion 258 is chamfered toward its innersurface, thereby providing a slanted surface 258A.

The hub member 238 and the flange members 240 are assembled together asfollows.

The leg portions 254 of one of the flange members 240 are inserted intothe gap between the outer and inner tubes 242 and 244 of the hub member238, and each flange portion 252 is pressed toward the hub member 238.In consequence, the respective retaining portions 258 of the legportions 254 are pressed so as to abut against the larger-diameterportion 248 formed on the inner tube 244, and the leg portions 254 thenadvance toward the inner side while having the slanted surfaces 258A onthe retaining portions 258 guided by the larger-diameter portion 248.

Since the leg portions 254 are deflected outwardly, the retainingportions 258 pass the larger-diameter portion 248. At the same time asthe retaining portions 258 have ridden over the portion 248, the shapeof the leg portions 254 are restored, whereby the retaining portions 258are retained by the rising surface of the larger-diameter portion 248.In this state, the flange portion 252 is in contact with thecorresponding end face of the outer tube 242, and the outer peripheralsurface of the annular protuberance 256 formed on the flange portion 252abuts against the inner peripheral surface of the outer tube 242. Theother flange member 240 is mounted on the hub member 238 from the sideopposite to the above-described flange member 240 in a manner similar tothe above. It is to be noted that the leg portions 254 of this flangemember 254 are disposed such as to be 45° out of phase with respect tothe leg portions 254 of the flange member 240 which has already beenmounted.

The thus assembled guide rollers 236 are respectively accommodated inthe left and right guide roller chambers 34 and 36 of the lower cassettecasing 10, as shown in FIG. 7. In this case, roller shafts 260 (seeFIG. 1) are respectively fitted on the projections 52 formed in the leftand right guide roller chambers 34 and 36 in advance.

Each of the roller shafts 260 is a metallic tubular member and has alarger-diameter portion 260A formed on the outer periphery of one endportion, the portion 260A having a diameter slightly larger than that ofthe other portion, as shown in FIG. 1. The roller shafts 260 arerespectively fitted on the projections 52, with the larger-diameterportions 260A directed downward. The guide rollers 236 are respectivelyfitted on the roller shafts 260 in such a manner that thelarger-diameter portion 250A of the hollow portion of the inner tube 244of the hub member 238 of each guide roller 236 is directed downward.Each guide roller 236 is supported in such a manner that the lower endface of the inner tube 244 abuts against the flange portion 52A formedaround the root portion of the projection 52, and the larger-diameterportion 250A of the inner tube 244 is rotatably supported by thelarger-diameter portion 260A of the roller shaft 260, and further, thesmaller-diameter portion 250B of the inner tube 244 is rotatablysupported by the upper portion of the roller shaft 260.

Brake Lever

As shown in FIGS. 1 and 10, the brake lever 262 is composed of acylindrical base portion 264, a reel engaging portion 266 projectingfrom the outer peripheral surface of the base portion 264, and a releasepiece engaging portion 268 projecting from the outer peripheral surfaceof the base portion 264, the portion 268 being 90° apart from the reelengaging portion 266, and these portions 264, 266 and 268 beingintegrally molded from a synthetic resin. The reel engaging portion 266has the same heightwise dimension as that of the base portion 264, sothat the former extends from the latter in such a manner that the upperand lower ends of the former respectively coincide with those of thelatter. A pawl 270 is formed at the distal end of the reel engagingportion 266, the pawl 270 being bent toward the side of the portion 266which is remote from the release piece engaging portion 268, and thepawl 270 further slightly extending downward. A spring retainer 271projects upwardly from the intermediate portion of the upper end surfaceof the reel engaging portion 266, the retainer 271 having its distal endbeing bent so as to extend in the same direction as the release pieceengaging portion 266 projects.

The release piece engaging portion 268 projects from the base portion264 by an amount smaller than that of the reel engaging portion 266 andhas a heightwise dimension smaller than that of the base portion 264.The portion 268 projects from the base portion 264 in such a manner thatthe upper end of the former coincides with that of the latter. A releasepiece abutting portion 272 is formed at the distal end of the releasepiece engaging portion 268, the portion 272 being bent so as to extendin the same direction as the reel engaging portion 266 projects andfurther slightly extending upwardly.

The other brake lever 274 has a symmetrical configuration with respectto that of the brake lever 262.

As shown in FIG. 7, the brake levers 262 and 274 are respectivelyaccommodated in the left and right brake lever chambers 64 in such amanner that the projections 68 formed in the chambers 64 are fitted intothe hollow portions of the base portions 264, respectively. After thebrake levers 262 and 274 have been thus fitted, the coil portions oftorsion coil springs 276 (see FIG. 1) are fitted on the projections 68,respectively. One arm of each of the springs 276 is retained by aprojection 70 formed in each of the left and right brake lever chambers64, and the other arm is retained by the spring retainer 271.

The brake levers 262 and 274 are biased by the respective torsion coilsprings 276 so that the lever 262 pivots clockwise as viewed in FIG. 7,while the lever 274 pivots counterclockwise. The reel engaging portion266 of the brake levers 262 and 274 extend into the left and right reelchambers 30 and 32 through the openings formed in the partition walls 74which partition the left and right brake lever chambers 64 from the leftand right reel chambers 30 and 32, respectively. The pawl 270 formed atthe distal end of each reel engaging portion 266 is positioned between apair of adjacent teeth 186 formed around the outer periphery of theflange 182 of each reel 180.

On the other hand, the release piece engaging portions 268 extend intothe release piece accommodating chamber 62 through the notches 72 formedin the partition walls 60 which partition the left and right brake leverchambers 64 from the release piece accommodating chamber 62.

It is to be noted that since the lower end surface of the base portion264 of each of the brake levers 262 and 274 abuts against and issupported by the flange portion 68A formed at the root portion of eachof the projections 68, the reel engaging portions 266 cannot come inslide contact with the bottom panel 12 of the lower cassette casing 10.Further, since the pawls 270 which have portions extending downwardlyfrom the reel engaging portions 266 are respectively positioned in therecesses 76 formed in the bottom panel 12 and, in addition, the flangeportions 68 are provided, there is no risk of the pawls 270 coming inslide contact with the bottom panel 12.

Release Piece

Referring to FIG. 1, together with FIGS. 11(A) and 11(B), a releasepiece 278 which serves as a brake canceling member consists of a bodyportion 280 having a substantially parallelepiped configuration, arectangular flange portion 282 projecting horizontally from the bottomof the base portion 280, and brake lever abutting portions 284, theseportions being integrally molded from a synthetic resin. The brake leverabutting portions 284 respectively project from the left and right endportions of the rear wall of the body portion 280, and the respectivelower ends of the portions 284 are integrated with the flange portion282.

The body portion 280 is made hollow and has a partition wall 286 whichdivides the hollow inside into two portions, that is, front and rearportions. The partition wall 286 has a slanted portion 286A which risesat an angle of about 60° from the rear end face of the opening at thelower side of the body portion 280. The slanted portion 286A is bent atits intermediate portion such as to extend upwardly, thus providing aslanted portion 286B which is connected to one end of the upper wall ofthe body portion 280, the other end of the upper wall being contiguouswith the front wall. The front wall is slanted so that the distancebetween the front and rear walls gradually increases toward the bottomof the release piece 278. A recess 288 is defined between the front walland the slanted portion 286B of the partition wall 286. It is to benoted that the left and right side walls of the body portion 280 projectbeyond the upper wall, and the projecting portions respectively defineslide contact portions 290 for slide contact with the upper cassettecasing 10.

When the release piece 278 is accommodated in the release pieceaccommodating chamber 62, the undersurface of the flange portion 282abuts against the bottom panel 12 of the lower cassette casing 10, andthe brake lever abutting portions 284 respectively face the releasepiece abutting portions 272 formed at the distal end of the releasepiece engaging portions 268 of the brake levers 262 and 274. The slantedportion 286A is positioned above the through-hole 66 formed in thecenter of the release piece chamber 62.

It is to be noted that the configuration of the release piece 278 is notnecessarily limited to that exemplified in this embodiment and may, as amatter of course, be such as that shown in FIG. 11(C).

Lock Plate

As shown in FIGS. 1 and 12, a lock plate 292 which serves as a means forlocking the guard panel consists of a cylindrical base portion 294, aguard panel engaging portion 296 extending from a position on the outerperiphery of the base portion 294, and a leaf spring portion 298extending from a position on the outer periphery of the base portion 294such as to project in a direction opposite to that of the guard panelretaining portion 296, these constituent portions being integrallymolded from a synthetic resin. The lower end of the guard panel engagingportion 296 is located slighly above the lower end of the base portion294, and the upper end of the portion 296 is located at the level of thevicinity of the longitudinal center of the base portion 294. A retainingblock 300 projects sidewardly from the lower portion at the distal endof the guard panel retaining portion 296, and a retaining cancelingblock 302 projects from the upper portion in the center of the portion296 in the same direction as the block 300 does.

The leaf spring portion 298 is relatively thin and has a relativelyshort length in terms of the heightwise direction of the base portion294. The portion 298 is bent at its intermediate portion such as toextend in the same direction as the block 300 projects. The lower endsurface of the leaf spring portion 298 is positioned slightly above thelower end of the base portion 294.

The lock plate 292 is, as shown in FIG. 7, accommodated in the lockplate chamber 40 in such a manner that the projection 83 formed in thechamber 40 is fitted into the hollow portion of the base portion 294.The distal end of the leaf spring portion 298 of the lock plate 292resiliently abuts against the inner side of the left side wall 16, sothat the guard panel retaining portion 296 is biased such as to pivotclockwise as viewed in FIG. 7. The portion 296 thus biased is pressed soas to abut against the lock plate retaining wall 84, and the distal endof the retaining block 300 projects from the opening 90, while thedistal end of the retaining canceling block 302 projects from the notch92.

Reel Retainer

As shown in FIG. 1, a reel retainer 304 is constituted by a leaf springformed from a single metallic flat sheet by bending and shearing. Theretainer 304 has three bores 306 provided in its proximal-side portionand a substantially triangular opening 308 provided in its free end-sideportion. The distal end of the free end-side portion of the retainer 304has a circular configuration.

The arrangement of the other reel retainer 310 is similar to that of theretainer 304. The configuration of the free end-side portion of theretainer 310 is the same as that of the retainer 304, but theproximal-side portion of the retainer 310 is extended so that theretainer 310 has a substantially V-shaped configuration as a whole.Three bores 312 and two bores 314 are provided in the proximal-sideportion of the retainer 310.

Each of the two contact members 316, which serve as external contacts,consists of an upper columnar portion having a spherical upper surfaceand a relatively large diameter, and a lower columnar portion having arelatively small diameter, the columnar portions being integrallymolded. The two contact members 136 have their lower columnar portionsrespectively inserted into the bores 314 formed in the reel retainer310. Then, the lower ends of the lower columnar portions are caulked,whereby the contact members 316 are secured to the reel retainer 310.

The reel retainer 304 and the reel retainer 310 which has the twocontact members 136 secured thereto are respectively secured to the leftand right reel chambers 128 and 130 of the upper cassette casing 104.The reel retainer 304 is secured to the top panel 106 in such a mannerthat the three projections 146 formed in the left reel chamber 128 arerespectively fitted into the three bores 306 of the retainer 304, andthe distal ends of the projections 146 are cauled by heating. Similarly,the reel retainer 310 is secured to the portion of the top panel 106within the right reel chamber 130. The two contact members 316 arerespectively fitted into the two through-holes 148 formed in the toppanel 106 such that the spherical upper end surfaces of the contactmembers 316 slightly project from the outer surface of the top panel106.

Connection of Upper and Lower Cassette Casings

The lower and upper cassette casings 10 and 104 are connected togetherin such a manner that the upper cassette casing 104 with the innersurface of the top panel 106 directed downward is overlaid on the lowercassette casing 10 with the inner surface of the bottom panel 12directed upward. As described above, the corresponding side surfaces ofthe projecting portions formed on the peripheral walls and the like ofthe cassette casings 10 and 104 contact each other, and the top surfaceof one of each pair of mating projecting portions contacts the surfacefrom which the other projecting portion rises, whereby both the cassettecasings 10 and 104 are connected together by means of spigot joint.

The cylindrical projections 150 formed on the upper cassette casing 104are respectively fitted into the hollow portions of the roller shafts260 to thereby support the roller shafts 260 in cooperation with thecylindrical projections 52 formed on the lower cassette casing 10. Thehollow portions of the cylindrical projections 168 formed on the uppercassette casing 104 respectively receive the columnar projections 68formed on the lower cassette casing 10, whereby the columnar projections68 are supported at both ends thereof. The hollow portion of thecylindrical projection 170 formed on the upper cassette casing 104receives the columnar projection 83 formed on the lower cassette casing10, whereby the projection 83 is supported at both ends thereof. Thecylindrical projections 172 formed on the upper cassette casing 104 arerespectively fitted into the hollow portions of the cylindricalprojections 98 formed on the lower cassette casing 10.

Tapping screws 318 are respectively inserted into the hollow portions ofthe cylindrical projections 52 and 98 through the openings in the bottompanel 12 from the outer side thereof. The tapping screws 318 are inthread engagement with the projections on the upper cassette casing 104which are respectively fitted to those on the lower cassette casing 10.It is to be noted that the head of each of the tapping screws 318 doesnot project from the outer surface of the bottom panel 12. In this way,the lower and upper cassette casings 10 and 104 are secured together inone unit, thus constituting a cassette casing body 320 such as thatshown in FIG. 13.

Guard Panel

Referring to FIG. 1, together with FIGS. 13 and 14, a guard panel 322,which serves as a cover for the cassette casing body 320, conslsts of afront wall 324, left and right side walls 326, 328, and an upper wall330. Projections 332 and 334 are respectively formed on the innersurfaces of the side walls 326 and 328 and at the upper portions on therear side thereof, the projections 332 and 334 extending parallel to thefront wall 324. The projection 332 formed on the left side wall 326 hasa relatively large diameter at its root-side portion and a relativelysmall diameter at its distal end portion. A projection 336 is formed onthe larger-diameter portion such as to project radially of theprojection 332. The diameter of the projection 334 formed on the rightside wall 328 is the same as that of the smaller-diameter portion of theprojection 332, and the longitudinal length of the projection 334 issubstantially equal to that of the smaller-diameter portion.

A recess 338 is formed in the lower portion at the rear end of the innersurface of the left side wall 326, one end of the recess 338 beingexposed at the undersurface of the wall 326. Two ridges are formed onthe right end portion of the outer surface of the upper wall 330, theridges constituting a pair of guide rails 340 which are to be connectedin series to the substantially U-shaped guide rails 176 constituted bythe ridges formed on the outer surface of the upper cassette casing 104.The degree by which the ridges (rails) 340 project from the outersurface is the same as that of the ridges (rails) 176. A recess 342 isformed in the left end portion of the inner surface of the upper wall330, the recess 342 opening to the rear surface of the wall 330. Fournotches 346A to 346D are formed in the lower portions of the front wall324 and the wall portion at the joint between the front wall 324 and theright side wall 328.

Mounting of Guard Panel on Cassette Casing Body

The guard panel 322 is mounted on the cassette casing body 320 after atorsion coil spring 344 has been disposed on the projection 332. Thespring 344 has its coil portion fitted on the larger-diameter portion ofthe projection 332, one end thereof being retained by the projection336, and the arm portion at the other end thereof being temporarilyretained by the recess 342 formed in the upper wall 330. As describedabove, the cassette casing body 320 has the shaft supporting bores 120and 126 formed at the joint portions between the lower and uppercassette casings 10 and 104. The projections 332 and 334 formed on theguard panel 322 are respectively fitted into the bores 120 and 126.

First, the projection 332 is fitted into the shaft supporting bore 120formed in the left side wall of the cassette casing body 320. Theprojection 332 has its smaller-diameter portion at the distal end fittedinto the shaft supporting bore 120 immediately after the position atwhich the arm portion of the torsion coil spring 344 is retained hasbeen shifted from the recess 342 to the recess 173 of the upper cassettecasing 104. Then, the projection 334 is fitted into the shaft supportingbore 126 formed in the right side wall of the cassette casing body 320.In this way, the guard panel 322 is mounted on the cassette casing body320, thus completing the assembly of the cassette as shown in FIG. 15.In this assembled state, the guard panel 322 is biased by the torsioncoil spring 344 such as to pivot toward the lower side as viewed fromthe front of the cassette.

Apparatus into Which Cassette is Loaded

FIG. 16 schematically shows a cassette holder 348 of an apparatus intowhich the cassette in accordance with this embodiment is loaded. Thecassette holder 348 is supported by a link-type lifting mechanism 350 sothat the holder 348 is movable toward the upper side of the apparatus.Two contacts 352 and 354 which are respectively constituted by leafsprings are disposed on the cassette holder 348 in parallel with thedirection (indicated by the arrow A in FIG. 16) in which the cassette isinserted into the apparatus, the contact springs 352 and 354 extendingdownwardly toward the inner side in the cassette inserting direction.Each of the contact springs 352 and 354 is bent at its distal endportion so that the distal end is directed upward.

A pressing block 356 is disposed at an opening provided in one of thesides of the cassette holder 348. The block 356 is secured to one end ofa leaf spring 358 in such a manner that the distal end portion of theblock 356 projects from the opening. Further, hook-shaped stoppers 360and 362 are formed on the bottom of the cassette holder 348, andthrough-holes 364 which respectively correspond to the through-holes 46of the lower cassette casing 10 are provided in the bottom of the holder348.

Operation of the Embodiment

The following is a description of the embodiment detailed above.

When the cassette is out of use, for example, when it is stored ortransported, it has an external appearance such as that shown in FIG.15. More specifically, as shown in FIG. 13(A), a portion of the tape222, which is led out from one tape inlet/outlet port 158 and guidedinto the other tape inlet/outlet port 158, is exposed at the front sideof the cassette casing body 320 constituted by the lower and uppercassette casings 10 and 104 rigidly connected together. The exposedportion of the tape 222 is positioned on the rear side of the guardpanel 322, since the panel 322 is in its closed position and covers thefront side of the cassette casing body 320. Thus, the guard panel 322covers the exposed portion of the tape 222 so as to prevent this portionfrom contacting any foreign matter, as well as covering the tapeinlet/outlet ports 158. Accordingly, the ports 158 are shielded fromlight in a relatively satisfactory manner.

When the cassette is out of use, the greater part of the tape 222 hasbeen rewound so as to be set on one of the reels 180 (the right-handreel, in this embodiment), and the leader tape 228 and the magnetic tape226 are positioned on the outer peripheral side of the roll of the tape222 wound on the reel 180. For this reason, no light practically entersthrough the tape inlet/outlet ports 158, and even if a slight amount oflight enters, there is no risk of the photosensitive tape 224 on theinner peripheral side of the tape roll being affected by the light.

The guard panel 322, which is in its closed position and covers thefront side of the cassette casing body 320, is maintained in thisposition by the action of the torsion coil spring 344 biasing the panel322. In addition, the guard panel 322 is locked by the lock plate 292 inorder to prevent the panel 322 from being undesirably opened against thebiasing force of the spring 344. The lock plate 292 is biased by theleaf spring portion 298 such that the distal end of the retaining block300 of the guard panel retaining portion 296 projects from the opening90 so as to engage with the recess 338 formed in the inner surface ofthe left side wall 326 of the guard panel 322 in order to prevent thepanel 322 from pivoting to open. It is to be noted that the distal endof the retaining canceling block 302 of the guard panel retainingportion 296 projects from the notch 92 and is exposed to the outside ofthe cassette casing body 320.

As to the reels 180, the convex portions 216 of the contact pieces 212integrated with the reels 180 are biased by the respective reelretainers 304 and 310, respectively, whereby the reels 180 are pressedagainst the bottom panel 12 of the lower cassette casing 10. The reels180 respectively close the through-holes 46 provided in the bottom panel12, and the triple partition wall consisting of the annularprotuberances 48, 196 and 50 isolates the interior of the cassettecasing body 320 from the outside. Therefore, even if the reels 180 areundesirably lifted, intrusion of dust and light is practicallyprevented.

The brake levers 262 and 274 are respectively biased by the torsion coilsprings 276 so as to pivot, and each of the pawls 270 is positionedbetween one pair of adjacent teeth 186 formed along the outer peripheryof the flange 182 of the corresponding reel 180. Accordingly, the reels180 are locked from turning, and the tape 222 is thereby prevented frombeing unwound loosely. The release piece 278 is positioned above thethrough-hole 66 formed in the bottom panel 12 of the lower cassettecasing 10 so as to close the through-hole 66, thereby preventingintrusion of dust and light through the through-hole 66.

In actual use, the cassette is loaded into the apparatus. As shown inFIG. 16, the cassette holder 348 which is disposed in the apparatus ismoved toward the upper side of the apparatus by means of the liftingmechanism 350 in response to the actuation of an ejector button (notshown). The cassette is inserted into the cassette holder 348 in thedirection of the arrow A shown in FIG. 16, with the guard panel 33directed toward the holder 348. When the leading end of the cassettereaches the approximately central portion of the cassette holder 348,the cassette contacts the contact spring 354. The bent distal endportion of the contact spring 354 first abuts against and rides on oneof the two ridges 340 formed on the guard panel 322, and immediatelythereafter, the distal end portion abuts against and rides on the otherridge 340. Before abutting against the guard panel 322, the contactspring 354 is placed in the position shown by the chain line in FIG.16(B), and after the abutment, the contact spring 354 is elasticallydeformed as shown by the solid line in FIG. 16(B).

As the cassette is further inserted, the contact spring 354 transfersfrom the ridges 340 to the two ridges 176 formed on the upper cassettecasing 104. Similarly, the other contact spring 352 first rides on theridges 340 and then transfers to the ridges 176. When the cassettereaches a point which defines the innermost position of its travel,portions of the front wall of the lower cassette casing 10 whichrespectively face the notches 346B and 346D formed in the guard panel322 abut against the respective stoppers 360 and 362 formed on thecassette holder 348.

In the above state, the bent distal end portions of the contact springs352 and 354 are positioned within the recesses 178 defined at theintermediate portions of the ridges 176 and are in resilient contactwith the contact members 316, respectively, which are positioned betweenthe right- and left-hand recesses 178 as viewed in the cassetteinserting direction. Further, when the cassette reaches the innermostposition of its travel, the pressing block 356 presses against theretaining canceling block 302 of the lock plate 292, thus causing theguard panel retaining portion 296 to pivot against the biasing forceapplied thereto from the leaf spring 298. In consequence, the retainingblock 300 is withdrawn into the opening 90, and the guard panel 322 isthereby unlocked. It is to be noted that before the cassette reachessaid position, the pressing block 356 is pressed by the left side wallof the cassette casing body 320 so that the leaf spring 358 isdeflected, and the block 356 is thereby withdrawn into the opening.

When the insertion of the cassette into the cassette holder 348 has beencompleted, the cassette holder 348 is manually or automatically pushedinto a predetermined position within the apparatus. During thisoperation, the notch 346A formed in the guard panel 322 engages with acover opening mechanism (not shown) which is disposed in the apparatus,thus causing the guard panel 322 to be gradually opened against thebiasing force of the torsion coil spring 344. When the cassette holder348 reaches a point which defines the innermost position of its travel,the guard panel 322 is completely opened.

During the operation of pushing the cassette holder 348, when the holder348 comes near said innermost position, a brake canceling pin (notshown) which is disposed in the apparatus enters the through-hole 66provided in the bottom panel 12 of the lower cassette casing 10 andgradually advances toward the inner side as the pushing operationprogresses. In this state, the release piece 278 is positioned above thethrough-hole 66. The brake canceling pin abuts against the slantedportion 286A of the release piece 278 and presses the latter. However,since the slide contact portions 290 of the release piece 278respectively abut against the guide walls 162 formed on the uppercassette casing 104, the release piece 278 thus pressed is preventedfrom moving upward.

Accordingly, the release piece 278 is moved while slide-contacting theguide walls 162 by means of the horizontal component of the pressingforce applied thereto from the brake canceling pin. During thismovement, the release piece 278 is prevented from moving laterally bythe projecting portions 166 of the guide walls 164. When the cassetteholder 348 is placed at the innermost position of its travel, the brakecanceling pin is positioned within the recess 288 formed in the innerside of the release piece 278. Since the release piece 278 is moved in astate wherein the through-hole 66 is closed, intrusion of dust and lightthrough the through-hole 66 is prevented during the movement of therelease piece 278.

In response to the movement of the release piece 278, the release pieceabutting portions 272 of the brake levers 262 and 274 are respectivelypressed by the brake lever abutting portions 284 of the release piece278, and the brake levers 262 and 274 are thereby pivoted against thebiasing forces of the torsion coil springs 276, thus causing the pawls270 to withdraw from the reels 180. Thus, the reels 180 are releasedfrom the brakes and allowed to turn.

When the cassette holder 348 is placed at the innermost position of itstravel, the reels 180 are, as shown in FIG. 8, mounted on respectivereel tables 376 which are disposed in the apparatus, and the shafts 378of the reel tables 376 are positioned within the hollow portions of theinner tubes 188, respectively, each shaft 378 having a plurality ofengagement pieces 380 projecting radially therefrom, and each engagementpiece 380 being positioned between each pair of adjacent projections200. It is to be noted that the reels 180, in this state, are not pushedupwardly by the respective reel tables 376.

The cassette holder 348, at the innermost position of its travel, islocked by a lock mechanism (not shown) which is provided in theapparatus so that the holder 348 is maintained in this position.

In the cassette, one of the reels 180 is turned by rotating thecorresponding reel table 376, while the other reel 180 is turned bymeans of the traction applied thereto through the tape 222. Theelectrically conductive layer of the photosensitive tape 224 iselectrically connected to the contact piece 212 disposed on the firstreel 180 through the electrically conductive adhesive tape 232. Thecontact piece 212 is electrically connected to the reel retainer 310 atthe convex portion 216, while the reel retainer 310 is electricallyconnected to the contact springs 352 and 354 disposed on the apparatusthrough the contact members 316 so that the retainer 310 is grounded tothe apparatus. Accordingly, the photosensitive tape 224 is constantlygrounded regardless of whether the reels 180 are turned or at rest.

After the use of the cassette, it is unloaded from the apparatus andstored. In this case, the ejector button (not shown) which is providedon the apparatus is actuated, and the cassette holder 348 is therebymoved toward the upper side of the apparatus. In this state, the guardpanel 322 is disengaged from the cover opening mechanism (not shown) andtherefore brought into its closed position by means of the biasing forceapplied thereto from the torsion coil spring 344. Since the releasepiece 278 is disengaged from the brake canceling pin (not shown), thebrake levers 262 and 274 are pivoted by means of the biasing forces ofthe torsion coil springs 276, respectively. In consequence, the brakelever abutting portions 284 of the release piece 278 are respectivelypressed by the release piece abutting portions 272 of the brake levers262 and 274, thus causing the release piece 278 to slide so as to reachits previous position. At the same time, each of the pawls 270 of thebrake levers 262 and 274 is positioned between one pair of adjacentteeth 186 formed along the outer periphery of the flange 182 of thecorresponding reel 180, thereby preventing the reels 180 from turning.

Then, the cassette is drawn out of the cassette holder 348 and stored.In response to the operation of drawing out the cassette, the retainingcanceling block 302 of the lock plate 292 is released from the pressureapplied thereto from the pressing block 358. In consequence, the guardpanel retaining portion 296 is pivoted by means of the biasing force ofthe leaf spring portion 298. As the guard panel retaining portion 296pivots, the retaining block 300 projects from the opening 90 and engageswith the recess 338 of the guard panel 322, thus locking the guard panel322.

Although the purpose of the tab 96 formed in the independent chamber 42is not particularly limited in this embodiment, the tab 96 can beapplied for various uses by arranging the apparatus such that it ispossible to detect whether the tab 96 is present or not, since the tab96 can be removed by cutting it off from the lower cassette casing 10.

As has been described above, the cassette for accommodating anelectrically conductive film in accordance with this embodiment offersthe following various advantages.

Since the upper and lower cassette casings are connected together bymeans of spigot joint, there is no risk of light entering the interiorof the cassette casing body through the joint between both the casings,and it is therefore possible to shield the light completely.

The partition walls are positioned between the left and right guideroller chambers and the left and right reel chambers, respectively.Therefore, any light entering through an tape inlet/outlet port which isnot completely shielded from the light cannot practically reach the leftand right reel chambers.

The torsion coil spring for biasing the guard panel so as to pivot isdisposed on the outer side of the shaft supporting bore formed in thecassette casing body for rotatably supporting the projection of theguard panel on which this spring is disposed. It is therefore possiblefor the guard panel to be mounted and removed even after the upper andlower cassette casings have been connected together.

Since the lock plate for locking the guard panel has its leaf springportion and retaining portions integrally molded, it is possible toreduce the number of required parts, facilitate the assemblingoperation, and decrease the total cost.

Since the upper cassette casing has the guide rails formed at portionsthereof which slide-contact the contact springs disposed on the cassetteholder, there is no fear of the cassette casing being scratched.Further, the recesses are formed in the guide rails which are providedso as to face each other across the external contacts, and they aredisposed in such a manner that the recesses which are respectivelypositioned on the right- and left-hand sides of the external contactsare offset from each other with respect to the center line extending inthe cassette inserting direction. In consequence, one contact springdoes not enter the respective recesses of the two parallel guide railsat the same time nor disengage therefrom at the same time. It istherefore possible for the contact springs to move smoothly. Since thereare provided two contact springs and two external contacts, even ifeither of them should have a conduction failure, grounding is reliablyeffected.

Since each of the guide rollers is constituted by a hub portion andflange portions which are produced as separate elements and are thenassembled together in one unit, the guide roller has no mold partingline which would be formed thereon by integral molding. Thus, it ispossible to obtain a highly accurate and smooth roller surface. Inaddition, the flange portions and the hub portion can readily beassembled in a single and simple operation without any need for abonding agent or the like. Further, since it is possible to obtain eachof the flange and hub portions as an integrally molded product, costsare reduced.

Each of the reels is accommodated in such a manner that the annularprotuberance formed on the undersurface of the flange is positionedbetween two annular protuberances formed on the inner surface of thelower cassette casing. Accordingly, these protuberances serve aspartition walls which practically isotate the interior of the cassettecasing body from the outside, so that intrusion of dust and light isprevented. Unlike the conventional video cassettes, the cassette inaccordance with this embodiment has a structure wherein each reel doesnot separate from the bottom surface of the cassette casing body evenwhen the reel is mounted on the reel table. It is therefore possible toreduce the clearance for the reel within the cassette casing body. Inconsequence, it is possible to reduce the thickness of the cassette fora particular tape width.

The release piece is adapted to reciprocate linearly and to be able toshift the brake levers while closing the through-hole for insertion ofthe brake canceling pin. Accordingly, intrusion of dust and lightthrough the through-hole is prevented.

Since each of the reels has a contact piece for grounding, it ispossible to ground an electrophotographic film through its electricallyconductive layer. A portion of the contact piece which abuts against theclamp is formed in the form of a leaf spring, and one end of the film ispressed and clamped between this leaf spring portion and the clamp. Itis therefore possible to obtain a reliable electrical connection betweenthe film and the contact piece. In addition, the film is retained on thereel by a satisfactorily large retaining force. A notch is formed in theleaf spring portion of the contact piece, and the bent plate portionformed on the clamp enters the notch while forcing the film into thenotch. Accordingly, the reliability of the electrical connection and themagnitude of retaining force are further intensified.

The electrically conductive layer of the electrophotographic film whichis electrically connected to the reel through the contact piece forgrounding is further electrically connected to the external contactsthrough the reel retainer which biases the reel so as to be pressedagainst the bottom of the cassette casing body. It is thereforeunnecessary to provide any special parts for electrically connecting thecontact piece and the external contacts. Further, the electricalconnection between them is reliably effected regardless of whether thereels are turned or at rest.

It is to be noted that in the above embodiment the reels 180respectively accommodated in the left and right reel chambers 30 and 32have the same structure and are respectively provided with the contactpieces 212 so that the same kind of element can be used in common forthe purpose of reducing the nunber of constituent elements. However, itis a matter of course that a reel having no grounding function may beaccommodated in the left reel chamber.

Although the present invention is applied to a cassette foraccommodating an electrophotographic film in the above embodiment, thepresent invention may be applied to any type of reel for winding amaterial in the form of a tape which needs to be grounded. In addition,the connection between the electrically conductive tape 222 and thecontact piece 212 may be attained by passing the contact piece 212through the tape 222, or by employing an electrically conductive rubber.

FIGS. 17(A) and 17(B) respectively show second and third embodiments ofthe present invention, in which it is possible for a single reelretainer to resiliently press a pair of reels so as to be retained. Areel retainer 366 shown in FIG. 17(A) has a projection 368 formed in itscenter by drawing, the projection 368 serving as an external contact.This reel retainer 366 has the projection 368 fitted into a through-hole(not shown) provided in the approximately central portion of the uppercassette casing in such a manner that the projection 368 is exposed atthe outer surface of the upper cassette casing.

The reel retainer 366 further has four bores 370 provided around theprojection 368. Four relatively short projections are formed on theinner surface of the upper cassette casing and around the through-hole.After the reel retainer 366 has been mounted in such a manner that theshort projections are respectively fitted into the bores 370, the distalends of these projections are caulked by heating, whereby the retainer366 is secured to the cassette casing. A pair of reels (not shown) arerespectively contacted by both longitudinal end portions of the reelretainer 366 so as to be resiliently retained. With this reel retainer366, the number of parts required for constituting reel retaining meansis only one. In addition, the external contact is formed by pressing. Itis therefore possible to reduce the number of required parts,advantageously.

A reel retainer 372 shown in FIG. 17(B) has an opening provided in itscenter. Into this opening is fitted the lower columnar portion of acontact member 374 which serves as an external contact, the member 374having an integrally molded structure which is constituted by an uppercolumnar portion with a relatively large diameter and a lower columnarportion with a relatively small diameter. After the lower columnarportion has been fitted, the distal end Of this portion is caulked,whereby the contact member 374 is integrated with the reel retainer 372as shown in FIG. 17(C). The configuration of the reel retainer 372 isthe same as that of the above reel retainer 366 except for a portion ofthe retainer 372 at which the contact member 374 is mounted.

It is to be noted that although the contact member(s), which serves asan external contact(s) exposed at the outer surface of the cassettecasing body, are secured to or formed on the reel retainer in the firstembodiment shown in FIGS. 1 to 15 and the second and third embodimentsshown in FIGS. 17(A) and 17(B), the external contact(s) may be separatedfrom the reel retainer. In such a case, it suffices to employ anappropriate means for electrically connecting both of them. In thiscase, it becomes possible to select as desired the position fordisposing the external contact(s), which leads to an increase in thedegree of freedom in designing the apparatus into which the cassette isloaded.

FIGS. 18 to 21 show in combination a fourth embodiment of the presentinvention, in which a reel retainer 372A similar to that in the thirdembodiment is employed, and a pair of reels 180 can be resilientlyretained by the retainer 372A alone.

In this embodiment, as shown in FIG. 20, a contact member 502 which isprovided on the cassette holder is inserted through a contact window 500formed in the upper cassette casing 104 so that the contact member 502comes in contact with the reel retainer 372A. Accordingly, the cassettecasing 104 in this embodiment is provided with no contact member such asthe contact members 316 in the first embodiment. It is to be noted thatthe contact piece 212 is secured to the reel 180 by screws 198A, asshown in FIG. 21.

A fifth embodiment of the present invention is shown in FIG. 22. In thisembodiment, an electrically conductive portion 510 is provided at theunderside of the flange 182 of the reel 180 so as to extend on the samecircumference which is concentrical with the reel 180, the portion 510being constituted by a metal foil, a spring, or a slip ring. A contactmember 512 which contacts the electrically conductive portion 510 isprovided at one position on the lower cassette casing 10 at which themember 512 faces the portion 510, and the contact member 502 on theapparatus contacts the contact member 512. The electrically conductiveportion 510 and the electrically conductive layer of the tape 224 areconnected by a lead plate 514 extending to the undersurface of theflange 182. When the reel 180 is turning, the ring-shaped electricallyconductive portion 510 slide-contacts the contact member 512, and thetape 224 is thereby grounded to the apparatus.

Conversely, the arrangement may be such that a contact member such as ametal foil or a slip ring is provided at one position on the undersideof the flange 182 such as to be connected to the lead plate 514extending to the flange 182, and a ring-shaped electrically conductiveportion which contacts the contact member is provided on the lowercassette casing 10.

It is also possible to employ an arrangement wherein a contact window isprovided in the lower cassette casing 10 in place of the contact member512, and a contact member on the apparatus is inserted through thecontact window so as to contact a contact member on the cassette side,as in the case of the aforementioned embodiment.

In this embodiment, the reel retainer 372A serves as a member whichsimply presses the reels 180 resiliently.

FIG. 23 shows a sixth embodiment in which a projecting edge portion 520is provided along the edge of the reel 180 which is entirely constitutedby an electrically conductive member or which has its surface platedwith a metal, and a contact member 522 is provided on the lower cassettecasing 10 so that the projecting edge portion 520 is brought intocontact with the member 522 by means of the weight of the reel 180. Inthis embodiment, since the surface of the reel 180 constitutes anelectrically conductive layer, no lead plate 514 is needed, and theperipheral surface of the reel 180 and the electrically conductive layerof the tape 224 are electrically connected by employing an electricallyconductive tape, an electrically conductive rubber, an electricallyconductive bonding agent and so forth. The grounding between the reel180 and the cassette holder is attained simply by bringing the contactmember 502 on the cassette holder into contact with the contact memberprovided on the lower cassette casing 10. When the reel 180 is turning,the projecting edge portion 520 of the reel 180 slide-contacts thecontact member 522, and the electrically conductive layer of the tape224 is thereby grounded to the apparatus.

Although each of the above embodiments exemplifies a cassette having apair of reels, it is, as a matter of course, possible to apply thepresent invention to cassettes of the single-shaft type in which anelectrophotographic film is fed from the cassette to an apparatus intowhich it is loaded.

ln the above embodiment, the tape 224 is described as anelectrophotographic film, but any film having an electrically conductivelayer which requires grounding, i.e., an electrostatic film or aphotoelectrophoretic (P.E.P.) film, can be applied to the presentinvention.. That is to say, the present invention can be applied to anycassette which requires grounding for a film having an electricallyconductive layer.

What is claimed is:
 1. A cassette for accommodating a film which has anelectrically conductive layer, comprising:(a) a reel body having arecess formed in the outer peripheral portion of its hub; (b) a contactpiece for grounding which is disposed on said reel body such that aportion of said contact piece is positioned in said recess; and (c) aclamp fitted into said recess so as to retain one end of said filmbetween the same and said recess and press said film against saidcontact piece, whereby the end portion of said film wound on said reelbody is grounded through said contact piece.
 2. A cassette according toclaim 1, wherein said contact piece is formed from a leaf springmaterial so as to clamp said film between the same and said clamp bymeans of a resilient force.
 3. A cassette according to claim 1, whereinsaid clamp is provided with a projection, and said contact piece isprovided with a notch such that said clamp projection enters said notchto clamp said film between said notch and said projection.
 4. A cassetteaccording to claim 3, wherein said contact piece has one end thereofsupported by said hub in a cantilever fashion.
 5. A cassette accordingto claim 3, wherein said clamp includes: a pair of leg plate portionseach having a step portion formed on the outer side thereof, said stepsrespectively engaging with step portions formed on said hub, therebypreventing said clamp from coming out of said recess; and a bent plateportion connecting said pair of leg plate portions, said bent plateportion having a bent portion which defines said projection, and saidbent plate portion causing said pair of leg plate portions to separatefrom each other, whereby said step portions of said leg plate portionsare rigidly engaged with the corresponding step portions provided onsaid hub.
 6. A cassette according to claim 4, wherein said notch extendslongitudinally of said contact piece and communicates with the outsideat one end of said contact piece.
 7. A cassette according to claim 4,wherein a portion of said contact piece which faces said clamp has itslongitudinally central portion projecting toward said clamp.
 8. Acassette according to claim 1, further comprising a cassette casing, anda reel retainer mounted on said casing, and wherein a portion of saidcontact piece contacts said reel retainer on the axis of said hub,thereby electrically connecting said film to said casing.
 9. A cassetteaccording to claim 8, wherein said reel retainer is biased so as topress against said contact piece.
 10. A cassette according to claim 9,wherein said reel retainer is constituted by a leaf spring.
 11. Acassette according to claim 9, wherein said reel retainer has a contactmember secured thereto, said contact member projecting to the outsidefrom said cassette casing so as to contact a contact provided on anapparatus into which said cassette is loaded.
 12. A cassette accordingto claim 11, wherein said contact member is a pin-like member whichsecures said reel retainer to said cassette casing.
 13. A cassetteaccording to claim 11, wherein the portion of said contact member whichprojects from said cassette casing is formed such as to have a sphericalshape, thereby ensuring the contact between said contact member and saidcontact on said apparatus.
 14. A cassette according to claim 11, whereinsaid cassette casing has a guide rail provided thereon near theprojecting portion of said contact member, said guide rail extending ina direction in which said cassette is inserted and having a recesspositioned to the side of said contact member, whereby said contact onsaid apparatus enters said recess when contacting said contact member.15. A cassette according to claim 13, wherein there are a plurality ofsaid contact members provided for one reel retainer, thereby allowingthe grounding to be reliably effected.
 16. A cassette according to claim14, wherein there are two of said contact members provided for one reelretainer, said contact members being arranged in series in the cassetteinserting direction, and there are a pair of said guide rails providedso as to face each other across said contact members.
 17. A cassetteaccording to claim 16, wherein said pair of rails have recesses providedon both sides of the row of contact members such that the recesses whichare positioned on one side of said row are offset from those which arepositioned on the other side as viewed in the cassette insertingdirection, and the imaginary straight lines connecting the diagonallyfacing recesses pass said contact members, respectively.
 18. A cassettefor recording an image on a film which has an electrically conductivelayer, which is wound on a reel disposed within a cassette casing, saidcassette comprising:(a) a contact piece for grounding which is mountedon said reel so as to electrically connect with said film; (b) a reelbody; (c) a fixed member secured to said cassette casing so as toslide-contact said contact piece which rotates together with said reelbody; and (d) a contact member electrically connected to said fixedmember and having a poriton thereof disposed on the outside of saidcassette casing.
 19. A cassette according to claim 18, wherein saidfixed member is a reel retainer which presses said reel through saidcontact piece.
 20. A cassette according to claim 18, wherein said reelbody is provided with a hub having a recess formed in the outerperipheral portion thereof, a portion of said contact piece beingdisposed within said recess, and wherein a clamp is fitted into saidrecess so as to press said film against said contact piece.
 21. Acassette according to claim 20, wherein said contact piece is formedfrom a leaf spring material so as to clamp said film between the sameand said clamp by means of a resilient force.
 22. A cassette accordingto claim 20, wherein said contact piece is provided with a notch suchthat a projection provided on said clamp enters said notch to clamp saidfilm between said notch and said projection.
 23. A cassette according toclaim 22, wherein said contact piece has one end thereof supported bysaid hub in a cantilever fashion.
 24. A cassette according to claim 22,wherein said clamp includes: a pair of leg plate portions each having astep portion formed on the outer side thereof, said steps respectivelyengaging with step portions formed on said hub, thereby preventing saidclamp from coming out of said recess; and a bent plate portionconnecting said pair of leg plate portions, said bent plate portionhaving a bent portion which defines said projection, and said bent plateportion causing said pair of leg plate portions to separate from eachother, whereby said step portions of said leg plate portions are rigidlyengaged with the corresponding step portions provided on said hub.
 25. Acassette according to claim 23, wherein said notch extendslongitudinally of said contact piece and communicates with the outsideat one end of said contact piece.
 26. A cassette according to claim 23,wherein a portion of said contact piece which faces said clamp has itslongitudinally central portion projecting toward said clamp.
 27. Acassette according to claim 20, wherein a portion of said contact piececontacts a reel retainer on the axis of said hub, said reel retainerbeing mounted on said cassette casing, thereby electrically connectingsaid film to said casing.
 28. A cassette according to claim 27, whereinsaid reel retainer is biased so as to press against said contact piece.29. A cassette according to claim 28, wherein said reel retainer isconstituted by a leaf spring.
 30. A cassette according to claim 28,wherein said reel retainer has a contact member secured thereto, saidcontact member projecting to the outside from said cassette casing so asto contact a contact provided on an apparatus into which said cassetteis loaded.
 31. A cassette according to claim 30, wherein said contactmember is a pin-like member which secures said reel retainer to saidcassette casing.
 32. A cassette according to claim 30, wherein theportion of said contact member which projects from said cassette casingis formed such as to have a spherical shape, thereby ensuring thecontact between said contact member and said contact on said apparatus.33. A cassette according to claim 30, wherein said cassette casing has aguide rail provided thereon near the projecting portion of said contactmember, said guide rail extending in a direction in which said cassetteis inserted and having a recess positioned to the side of said contactmember, whereby said contact on said apparatus enters said recess whencontacting said contact member.
 34. A cassette according to claim 32,wherein there are a plurality of said contact members provided for onereel retainer, thereby allowing the grounding to be reliably effected.35. A cassette according to claim 33, wherein there are two of saidcontact members provided for one reel retainer, said contact membersbeing arranged in series in the cassette inserting direction, and thereare a pair of said guide rails provided so as to face each other acrosssaid contact members.
 36. A cassette according to claim 35, wherein saidpair of rails have recesses provided on both sides of the row of contactmembers such that the recesses which are positioned on one side of saidrow are offset from those which are positioned on the other side asviewed in the cassette inserting direction, and the imaginary straightlines connecting the diagonally facing recesses pass said contactmembers, respectively.
 37. A cassette according to claim 18, whereinsaid contact member is provided on a cassette holder and is insertedfrom the outside of said cassette casing.
 38. A cassette according toclaim 18, wherein said contact piece is mounted on a flange portion ofsaid reel.
 39. A cassette for recording an image on a film which has anelectrically conductive layer which is wound on a reel disposed within acassette casing, said cassette comprising:(a) a reel body; (b) a contactpiece for grounding which is mounted on said reel body so as toelectrically connect with said film; (c) a contact member secured tosaid cassette casing so as to electrically connect with said contactpiece and having a portion thereof exposed to the outside of saidcassette casing; and (d) a guide rail provided near the exposed portionof said contact member, said guide rail extending in a direction inwhich said cassette is inserted and having a recess positioned to theside of said contact member, whereby a contact provided on an apparatusinto which said cassette is loaded enters said recess when contactingsaid contact member.
 40. A cassette according to claim 39, wherein saidcontact member is connected to a reel retainer which is secured to saidcassette casing so as to slide-contact said contact piece which rotatestogether with said reel body.
 41. A cassette according to claim 40,wherein there are two of said contact members provided for one reelretainer, said contact members being arranged in series in the cassetteinserting direction, and there are a pair of said guide rails providedso as to face each other across said contact members.
 42. A cassetteaccording to claim 40, wherein said pair of rails have recesses providedon both sides of the row of contact members such that the recesses whichare positioned on one side of said row are offset from those which arepositioned on the other side as viewed in the cassette insertingdirection, and the imaginary straight lines connecting the diagonallyfacing recesses pass said contact members, respectively.